Improvement in mills for grinding corn



Pa ented Ian 25, 1870.

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JAMES J. JOHNSTON, OF ALLEGHENY, PENNSYL ANIA, ASSIGNOR TO HIMSELF AND JOHN LOOKIE, OF WASHINGTON, DISTRICT OF COLUMBIA.

Lciters Patent No. 99,205, dated Ja-mza/ry 25, 1870.

IMPROVEMENT INMILLS FOR'G-RINDING CORN, 8w.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern:

Be it known that I, JAMES J. JOHNSTON, of the city and county of Allegheny, and State of Pennsylvania, have invented a new and useful Improvement in Mills for Grinding Corn, &c.; and I do hereby dclare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

Thenature of my invention consists in the combination of two disks, of different diameters, each rotating, with a different speed, in. opposite direction,

and each provided with a cutting or grinding-surface.

To enable others skilled in the art to construct and use my invention, I will proceed to describe its construction and operation.

, In the accompanying drawings, which form part of my specification' Figure 1 is a side elevation of my improvement in mills for grinding corn, &c.

Figure 2 is an end elevation of the same.

Figure 3 is a side elevation of the larger size of the mil Figure 4 is a vertical and longitudinal section of the same.

Figure 5 is atop view, or plan of the same.

Figure 6 is a transverse section of the grindingdisks, at line y of fig.

In the accompanying drawings- A represents-a box or chest, in which is pivoted, at w, the frame B for the small size of the mill.

To the frame B are hinged legs 0, for holding the frame B atthe desired angle. By thus pivoting the frame B, and providing it with legs, hinged to it, the frame may be folded so that the entire mill may be lowered down into the box or chest A, and covered with the lid Z, hinged at y.

Y The frame for the small size of the mill should be made of cast-iron, but may be made of wood, or other material, if desired; but cast-iron will be found to be cheaper, and will answer every purpose desired-in the frame.

The large grinding-disk D is secured on the shaft marked 1, which. is provided with a small wheel, at, which gears into a larger wheel, h, on the shaft marked 2, on the inner end of which is secured the small grinding-disk f; and on the outer end of the shaft, is a driving-pulley, m, (instead of which may be used a crank, w, as represented in figs. 3 and 5v of sheet B.)

On the inner edge of the rim at of the disk D is secured a disk, e, with an opening in the centre of it, for the shafts 1 and 2 to pass through.

The disk D is provided with a steel ring, 4, the inner surface of which is provided with cutting or-grin d-f ing-teeth, similar to the teeth of a file or woodrasp.

The disk f is also provided with a steel ring, as indicated at 3, in figs. 4 and 5. The outer surface of this ring is also furnished with cutting or grindingteeth, similar to those of ring 4, but should be larger.

The rings should be secured to their respective disks, so as to prevent them from moving on the one, or in the other.

The rings may be cast of metal, (cast-iron,) and subsequently annealed, and then provided with the cutting or grinding-teeth, after which they may, by the process of cementation, be converted into steel.

g represents the hopper, which is provided with inclined bottom, and a conductor, 0, as shown in figs. 1

and 2 of Sheet A. The outlet of the hopper may be provided with rotating wings, similar to those of a propeller-wheel, and thereby regulate the feeding of the grain into the mill.

s represents the chute, for carrying off the meal or flour, which may afterward be sifted or bolted, and the bran thereby separated from it.

The journal-bearings for the shaft 2 should be so arranged that their position can be varied, and thereby regulate the space between the cutting and grinding-surfaces of the rings 3 and 4.

The disks D and f should be made of a good article of cast-iron, but their cutting and grinding-surfaces should be made of steel, as hereinbeforedescribed.

The operation of the mill is as follows:

The grain is fed into the mill so that it will fall in between the disks at R, and the-revolving the disks will cut and grind it, carrying the meal or flour into the space marked R; and the revolving of the large disk will carry it up and against the part marked P, which will cause it to pass into the chute s, and thereby convey it from the grinding-disks.

The small disk f, revolving slower, and in an opposite direction to the large disk D, the following results follow:

First, the grain will never wedge in between the disks.

Second, the cutting is accomplished with but little friction, and a small amount of power.

.Third, a back-action of the cut or ground particles of the grain is produced,'whereby they are still further reduced to flour by the friction of one particle upon the other, and brought a second time in contact with the grinding-surfaces of the disks.

Fourth, the increased speed andgiinding-surface of the large disk causes the grain to be brought in be: tween the cutting and grinding-surfaces of disks,- and carries the ground meal or flour into the chute, which conveys it fromthe mill.

The advantage of constructing the cutting andgrinding-surfaces of the disks in the form and manner herein described, consists in being enabled to renew said grinding and cutting-surfaces at a small expense.

Having thus described the nature, construction, and operation,

What I claim, as of my invention, is

1. The combination of .two disks, one Within the other, and of different diameters, each rotating with a different speed and in opposite direction, and provided with cutting and grindingsurfaces, substantially as herein described.

2.- Constructing the rings 3 and 4 of the disks f and D of cast-iron, and subsequently annealing and subjecting them to a process of cementatipn, as herein described, and for the purpose set forth.

JAMES J. JOHNSTON.

Witnesses:

EDM. F. BROWN, Joan Loom. 

